isCgoImport accounts for back-quoted "C" import

format/format.go

@@ -833,13 +833,21 @@ func identEqual(expr ast.Expr, name string) bool {
 //
 // import "C"
 //
+// or the equivalent:
+//
+// import `C`
+//
 // Note that parentheses do not affect the result.
 func isCgoImport(decl *ast.GenDecl) bool {
  if decl.Tok != token.IMPORT || len(decl.Specs) != 1 {
  return false
  }
  spec := decl.Specs[0].(*ast.ImportSpec)
- return spec.Path.Value == `"C"`
+ v, err := strconv.Unquote(spec.Path.Value)
+ if err != nil {
+ panic(err) // should never error
+ }
+ return v == "C"
 }
 
 // joinStdImports ensures that all standard library imports are together and at

testdata/scripts/cgo.txt

@@ -10,18 +10,36 @@ package p
 import "C"
 import "os"
 
+import `C`
+import "os"
+
 import "C"
 import (
  "io"
  "utf8"
 )
 
+import `C`
+import (
+ "io"
+ "utf8"
+)
+
 -- foo.go.golden --
 package p
 
 import "C"
 import "os"
 
+import "C"
+import "os"
+
+import "C"
+import (
+ "io"
+ "utf8"
+)
+
 import "C"
 import (
  "io"